AWL builds complete production line for suspension beams for trailer axles for Daimler

In 2009 AWL built a production line for Kirchhoff Automotive for producing the suspension beam for Daimler trailers. A creative and innovative AWL team, in close cooperation with Kirchhoff, developed a unique line capable of producing 160,000 suspension beams per year. And that's just the beginning. The production line can easily be scaled up to 200,000 suspension beams per year.

Brief introduction Kirchhoff

Kirchhoff Automotive is one of the leading suppliers of metal structures in the automotive industry. This year, this traditional but very innovative family owned company has existed for 225 years and can look back on a very interesting and exciting history.

Today it employs more than 3,500 employees worldwide, of whom 500 work in the plant at Iserlohn, which is one of the largest and oldest of Kirchhoff’s plants and also the location where the suspension beam for the Daimler trailer is produced.

We have been talking to Mr. A. Rath, Plant Manager, and Mr. T. Müller, who is responsible for the division’s Hot Forming & Trailer systems. Both are employed by Kirchhoff and were closely involved in establishing the production line for the suspension beam.

Kirchhoff and AWL have enjoyed pleasant cooperation dating from the time AWL introduced the first standard cells and Kirchhoff was looking for a standard to start welding bumpers. They were seeking to bring quality, price and cycle time together in the right way. The solution? The semi-automatic welding machines from AWL, with operators inserting or removing parts, but in which the welding process is automated.

Mr. Rath says: "AWL has always been a very solid partner. Not only does AWL deliver reliable machines, the company is innovative and thinks with us. That makes our job easier"

In October 2007 AWL received the order for a new production line for the production of suspension beams for trailer axles. "We had reached the capacity limit with the old production line and the machine was really on its last legs, making the decision to install a completely new line fairly easy" says Müller.

AWL proceeded expeditiously from the start. Kirchhoff's ideas were enthusiastically and creatively incorporated into draft proposals and there was a great deal of contact between both parties to compile an optimum configuration. Rath explains: "AWL's experience in welding and our experience with the product itself have resulted in a concept that seems like a quantum leap compared to the old production line. The cycle time, the stability and reliability of the process, the quality of the product and even the energy consumption are excellent.

As many processes take place in the production line, like milling and welding, it was decided that Kirchhoff employees working with the machine should all follow a course at AWL. Müller explains: "Although the machine is very easy to use and very intuitive, our employees have to know how everything works. The fact that AWL wrote a special operator manual is unique. It is little things like that, we really appreciate from AWL.

For Kirchhoff it was the first time they used the AWL remote service, which is based on VPN technology. "What a godsend. This has saved us so much time and effort; certainly during the first six months when minor adjustments were made. Remote Service by AWL allowed us to quickly diagnose and fix the problem online," Müller continued.

The machine has now been in operation for one year and runs 16 hours per day in two shifts. Currently, Kirchhoff is using less than 100% of the machine’s capacity. "We are very positive about the future, the market is recovering slowly, and we expect to reach the full potential of the machine very soon," says Rath. This equates to 160,000 suspension beams per year with a fifteen shift production. A major advantage of the machine is that it is modular. When production needs to be further increased, a welding station or milling station can be added to the line fairly easily so that 200,000 suspension beams per year can be produced.

Muller says: "The integration of separate systems in the logistics and the safety of the overall circuit are special. It is nice for operators to work here. The production line is fully transparent and straightforward, which suits modern production.

The future looks bright. Kirchhoff is in deliberations with their client about the optimization of the suspension beam, where extreme demands placed on the suspension are combined with lightweight materials resulting in an obvious weight reduction of a trailer, which is not a luxury in these times of environmental awareness. "Should that affect the manufacture of the suspension beam and we need a new production line, we know that AWL will be an excellent partner," concludes Rath.

The production

The production line for the suspension beam for trailer axles has a capacity of 160,000 units. It takes about four hours before a suspension beam has gone through the entire production. At any given point in the production there are over 100 suspension beams in the process.

The suspension beam weighs between 25-35 kilograms, depending on the variant, and consists of five parts: two half-shells, a bush and two thick reinforcement plates

The half shells are placed on a conveyor belt. The variant is checked and the handling robot places the half-shells in the milling machine where the weld is pre-processed. After milling, the robot places the half-shells on a stand which goes via a conveyor belt to the first welding station. At the welding station the shells as a whole are picked up and placed in a fixture.
The reinforcement plates are added and the tack welds are made by the robot.

Through a buffer system, that in case of a malfunction ensures the machine can keep on producing, the suspension beam goes to the welding station. By means of a track the suspension beam can be placed on several locations for welding, which ensures optimal use of capacity. The welding takes place with a fixed torch where the robot guides the guide suspension.

After welding, the suspension beams are hung on a conveyor belt to cool. This belt is also a buffer for the production. The suspension beam then goes to a milling machine that smoothes the reinforcement plates, drills the holes, produces threads and smoothes the open sides of the suspension beam.

The suspension beam is transported to the next station where the bush is added and welded. After welding, the suspension beam is marked and placed on the issue desk. The suspension beam is now ready.

Key features of the production:

• Integration of different processes such as milling, welding, part handling and logistics buffers (control security)
• Logistics (transport, buffer, cooling)
• Multi-purpose robots
• Ring orientation supply
• Jiggles welding by using fixed torch
• Thick plate welding (10 mm)
• Robot Handling
• Emergency Strategies for each process step

Basic information:

Footprint: 900m2
Capacity: 160,000
Lead time: 4 hours (100 unit in process)
Technologies: Arc Welding
Milling
Handling
Logistics
Variations: 7